*{
    margin: 0;
    padding: 0;
}
body{
    background: url(../images/background.png);
    position: relative;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
}
#hero{
    background: url(../images/herofly.png) ;
    width: 67px;
    height: 80px;
    position: absolute;
    bottom: 10%;
    left: 48%;
}
.center-content {
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    align-items: center;
    text-align: center;
    height: 100%; /* 设定高度 */
  }
#fraction{
    font-size: 20px;
}
#begin{
    display: none;
}